Excision Repair Affects the Specificity of UV Mutagenesis in the lacI+ Gene of Escherichia coli: Possible Involvement of Secondary DNA Structure
Using a system which allows the determination of 72 base pair changes in the lacI+ gene of Escherichia coli carried on an F' plasmid, it was found that the distribution of UV-induced mutations occurring in a ΔUvrB strain was only different at one particular site when compared to the wild-type strain. It is proposed that secondary DNA structure is important in the UV-induction of mutation, which is discussed with reference to the formation of modified tRNA genes: nonsense suppressors. Furthermore, the mutational spectrum obtained at low UV fluence in the ΔUvrB strain was significantly different from that at high UV fluence.
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